Tandem Pump, Checking

WARNING: This page is about a different car, the 2006 Volkswagen Jetta and 2005 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Supply Pressure, Checking

Special tools and workshop equipment required

Test unit for tandem pump VAS 5187
Torque wrench V.A.G 1331
Vehicle diagnosis, testing and information system VAS 5051 B, VAS 5052 or VAS 5053
Diagnostic cable VAS 5051/6A

Test Conditions

Coolant temperature must be at least 85° C.
Pump-Injector Unit OK.
Fuel filter and fuel lines must not be plugged.
The check valve in the fuel supply hose must be OK.

Procedure

-- Remove engine cover.

One Piece Engine Cover

Fig 1: Identifying Removal Of One Piece Engine Cover

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Pull the one piece front engine cover -arrows A- upward with a quick jerk and then pull the lower mount -arrow B- forward.

Two Piece Engine Cover

Fig 2: Identifying Removal Of Two Piece Engine Cover

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

On the two piece engine cover, first pull the outer cover upward with a quick jerk -arrows in the upper illustration-, then pull the inner engine cover upward with a quick jerk -arrows in lower illustration-.

-- Disconnect electrical harness connector -2- at Mass Air Flow (MAF) sensor -G70-.

Fig 3: Identifying Ventilation Hose -1-, Electrical Harness Connector -2-, Spring-Type Clip -3-, Bolt -4- And Intake Manifold -5-

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Disconnect the ventilation hose -1- and disengage it from the bracket -arrow-.

-- Open the spring-type clip -3- using spring-type clip pliers VAS 5024A and disconnect the intake hose from the Mass Air Flow (MAF) sensor -G70-.

-- Disconnect the intake manifold -5- from the air guide.

-- Unfasten bolt -4- and remove air filter housing and mass air flow sensor.

WARNING:

The fuel or fuel lines in fuel system can become very hot (danger of scalding)!
In addition, the fuel system is under pressure! Before opening the system, place rags around the connection area and release pressure by carefully loosening the connection!
Wear protective goggles and protective gloves when working on the fuel system!

-- Remove the locking bolt -arrow-.

Fig 4: Identifying Plug

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Connect the pressure gauge VAS 5187 as shown.

Fig 5: Identifying Pressure Gauge VAS 5187

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Install the air filter housing with the Mass Air Flow (MAF) sensor and connecting pipe.

-- Start engine and run at idle speed.

-- Connect the vehicle diagnostic, testing, and information system VAS 5051B and select operating mode "Vehicle On-Board Diagnostics (OBD)".

-- Press button "01 - Engine Electronics" on display.

-- Press diagnostic function "08 - Read Measuring Value Blocks".

-- Enter display group "1" via the number keypad and confirm input by pressing the Q button.

-- Read the idle RPM in display field "1".

-- Increase engine speed to 4000 RPM.

-- Observe pressure displayed on pressure gauge.

Specified value: min. 7.5 bar

If the specification is not obtained:

-- Clamp the return line closed between the fuel filter and the tandem pump with a hose clamp.

-- Increase engine speed to 4000 RPM.

-- Observe pressure displayed on pressure gauge.

Specified value: min. 7.5 bar

If the specification is now obtained:

Pressure loss at the pump-injector unit.

-- Replace the O-rings of the pump-injector unit PUMP INJECTOR UNIT .

If the specification is not obtained:

-- Replace the tandem pump TANDEM PUMP .

NOTE:

After removing the test device, fasten the locking bolt with 25 Nm. Always replace the sealing ring.

Internal Leakage, Checking

NOTE:

After reinstalling a tandem pump, for example after replacing or repairing a cylinder head, or after replacing an engine, the tandem pump must absolutely be checked for internal leakage between the fuel and oil side. Fuel or oil leakages can cause damage to the engine.

Special tools and workshop equipment required

Turbocharger testing unit V.A.G 1687

Procedure

Read safety precautions before beginning work FUEL SUPPLY SYSTEM SAFETY PRECAUTIONS .

Observe the rules for cleanliness CLEAN WORKING CONDITIONS .

WARNING:

The fuel or fuel lines in fuel system can become very hot (danger of scalding)!
In addition, the fuel system is under pressure! Before opening the system, place rags around the connection area and release pressure by carefully loosening the connection!
Wear protective goggles and protective gloves when working on the fuel system!

-- Disconnect the fuel supply hose (white marking) and the fuel return hose (blue marking) to the tandem pump. Refer to "Supply hose" and "Return hose" under: CYLINDER HEAD ASSEMBLY OVERVIEW .

-- Seal the fuel return connection on the tandem pump with a blanking plug; secure the plug with a spring clamp.

Prepare it as follows:

-- Unscrew pressure regulator valve -2- completely and close valves -3- and -4-.

-- Connect the test connector -5- testing unit for turbocharger V.A.G 1687 to the tandem pump fuel supply connection using a commercially available compressed air connection and a piece of a fuel hose; use a spring clamp to secure it.

Fig 6: Identifying Pressurized Air Hose Connected To Testing Unit For Turbo Charger V.A.G 1687

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

NOTE:

In order to be able to turn pressure regulator valve -2-, rotary knob must be pulled upward.

-- Connect pressurized air hose -1- (pressurized air supply) to testing unit for turbocharger V.A.G 1687.

Fig 7: Identifying Pressurized Air Hose Connected To Testing Unit For Turbo Charger V.A.G 1687

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

NOTE:

If water is located in viewing glass, drain it via water drain plug -6-.

-- Open valve -3-.

-- Set pressure to 1.0 bar using pressure regulator valve -2-.

CAUTION:

The maximum test pressure is 1.3 bar and must not be exceeded.

-- Open valve -4- and wait until testing circuit has filled. If necessary, continue to regulate pressure to 1.0 bar.

-- Closes the valve -3-, in order to maintain the pressure and observe the drop in pressure for 1 minute.

If there is no pressure drop, then the tandem pump can be used again; if there is a pressure drop, then the tandem pump must be replaced.